New `owner_type` field for metafield declarations in Checkout and Customer Account UI extensions, required in 2027-01
Shopify developer change
MerchantDiff detected this entry in Shopify's official developer changelog on October 08, 2026.
This Shopify update is categorized as Action Required, API, Update, Checkout UI, Customer Accounts, 2026-10.
What changed
Metafield declarations in [[extensions.metafields]] and [[extensions.targeting.metafields]] accept a new owner_type property. owner_type names the resource that owns the metafield, such as PRODUCT or CUSTOMER. Shopify uses owner_type to fetch only the metafields from the resource types your extension needs, which improves extension performance. On API version 2027-01 and later, every metafield declaration must include owner_type.
Who is affected
Checkout and Customer Account UI extensions that declare metafields in shopify.extension.toml and use API version 2027-01 or later are affected. Extensions that don't declare metafields in shopify.extension.toml are unaffected.
What action may be needed
On API version 2027-01 or later, deployments will be blocked if any metafield declaration is missing an owner_type. Add owner_type to each metafield declaration before you upgrade. You can add it now on 2026-10. To migrate: Open your extension's shopify.extension.toml file and add the appropriate owner_type value for each metafield declaration.
Use the official Shopify entry below as the source of truth for technical implementation details, affected APIs, migration instructions and deadlines.
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